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FOCUS ON CROP SCIENCE RESEARCH

Dr David Lawrence, who recently retired as head of R & D at Syngenta, spoke at the recent seminar: Innovation in crop production for productivity and biodiversity (September CPM) organised by the UK’s Society of Chemistry and Industry and hosted by Syngenta at Jealott’s Hill research station. A biochemist by training, Dr Lawrence has overseen agrochemical research based on conventional crop protection chemistry, plant growth regulation and developments in plant biotechnology and genomics.  He kindly agreed to share his views on the past experiences and future prospects for global crop science research with Crop Protection Monthly.  Bruce Knight posed the questions.

Looking at the outputs from chemical synthesis, how do you see the current success rate and the future needs?

The success rate, in terms of the number of new active ingredients approved for marketing has remained surprisingly resilient. The number of new approvals per year more or less matches the trend in expenditure.  This is in contrast to pharmaceuticals where the spend has risen dramatically but the discovery rate has not kept up.

Resistance means that there is a continuing need for new modes of action, but in terms of gaps to be filled, the most critical need is for herbicides, where fewer novel mechanisms have been found recently. Virtually every class of herbicide on the market is demonstrating some form of resistance. Glyphosate, in particular, the world’s most widely used herbicide, needs either partners or an alternative. With insecticides and fungicides we are much better placed.

 Do you see any significant changes coming about in the efficiency of molecule discovery?

Ultra high level screening has not really delivered. The principle is based round the use of genomics to screen activity based on a specific mode of action. But for agrochemical activity this gives up the huge advantage of being able to screen on whole organisms and not to limit the potential mechanisms which might be found. Using natural products as sources of actives, or as leads for chemical synthesis, has shown continued success such as with the pyrethroids and the strobilurins. The problem is that from first indication to successful commercialisation can take 10 to 20 years. Successes are elusive and it takes persistence and a bit of luck.

 Although our knowledge of protein structures has much improved we are still a very long way from rationally designing active ingredients. We understand enough to see why a potent ligand works, but, unfortunately, just not enough to design new ones from scratch. I have to assume this will come – but do not know when?

What sort of organisation is best placed to achieve success?

As a director of research I have always recognised that size in itself is not the answer. It’s about teams of people who create the right environment for innovation to flourish. 

Geographically and culturally there are significant differences around the world as well. Western Europe still dominates in terms of commercially successful discoveries, notably Germany, Switzerland and the UK. Laboratories in the US, surprisingly, have not done as well and many companies have disappeared. It is too early to tell whether the emerging economies, China and India, while clearly good at manufacturing high quality chemicals, can also invent.  

What is your judgement on the future of genetic modification in crop production? 

Clearly GM crops are having an impact, but technology itself is tricky, and the range of traits which have been discovered is small, and really only a handful of input traits in a few crops make money.  In practice, the number of modified genes that are commercially relevant today are just three to four variations around glyphosate resistance, five to six variations delivering Bt toxins and one or two others.

However, these GM crops have brought huge benefits to growers. One of the problems is that consumers cannot see these benefits, but the segregation from conventional crops that Europe and Japan requires is becoming increasingly costly to the consumers in these countries.

The challenges are to discover more traits, ideally ones that consumers can recognise and to shorten development times. The typical development timetable is slow, up to 15 years from concept to commercialisation. The technology is still quite primitive, as it generally needs a number of genes to deliver reliably the desired traits.

 You have had a particular interest in plant performance. Is it still a productive area for research?

Within major companies the research effort in the 1970s and 1980s in trying to find chemical plant growth regulators was comparable to that for insecticide discovery.  But just a few compounds, mainly growth retardants, were commercialised. The problem was that screening was hard, and responses in the field were affected so much by the weather and plant variety. However, we know from experience that a few molecules originally developed as fungicides or insecticides have a positive effect on growth and stress tolerance in the absence of pests. The challenge is to understand how these work, and find reliable ways to find new molecules which are purely growth enhancers.

What about enhanced plant performance by other means?

Clearly performance can be enhanced by the selection through plant breeding of natural traits. For multigenic traits such as yield, this may well be a more successful approach than GM which deals with just a few genes at a time. The combination of GM traits with natural traits and tailoring chemicals to the genetics may well be the best way forward. But we need a better understanding of plant growth mechanisms combined with new chemicals before major breakthroughs can be realised.

 Do you believe that plant science and technology can meet the challenges to feed the world over the coming decades?

Climate change and living in a low-carbon world will significantly add to the challenge, but I remain firmly optimistic. Agricultural practices will have to adopt a more sustainable approach, but the polarisation of GM and organic is really standing in the way of this.  I believe the answer will come from a combination of new chemistry, GM traits, plant breeding and some of the techniques, such as rotations, inter-cropping and ‘green manure’ espoused by the organic movement . 

 Website design advisor: Jane Slade (RACC) 

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